The present technology relates to a correction circuit correcting a waveform of a current pulse to be applied to a surface-emitting semiconductor laser that emits laser light from a top face thereof. The present technology also relates to a drive circuit and a light emission unit that include the correction circuit. Further, the present technology also relates to a method of correcting the waveform of the current pulse to be applied to the semiconductor laser.
The surface-emitting semiconductor laser emits light in a direction perpendicular to a substrate, unlike an existing semiconductor layer of a Fabry-Perot resonator type. In the surface-emitting semiconductor laser, a number of resonator structures are allowed to be arranged in a two-dimensional array pattern on the same substrate. Therefore, the surface-emitting semiconductor laser has been attracted attention recently in technical fields of data communication, printers, etc.
The surface-emitting semiconductor laser typically has a mesa-type resonator structure in which a lower DBR layer, a lower spacer layer, an active layer, an upper spacer layer, a current confining layer, an upper DBR layer, and a contact layer are laminated in order on a substrate. In such a semiconductor laser, an oscillation wavelength is determined depending on an effective resonator length of the resonator structure, and magnitude of optical output is maximized at an emission wavelength corresponding to a band gap of the active layer. Therefore, typically, the resonator structure and the active layer are so configured that the effective resonator length of the resonator structure is equal to the emission wavelength of the active layer (see Japanese Unexamined Patent Application Publication No. 2008-306118).